Inge Balswick had a problem with this recipe:
:0fhw
* !^Subject:[ ]*\[Cirrus\]
* ^Subject:[ ]*\/[^ ].*
| formail -I"Subject: [Cirrus]$MATCH"
... because it adds "[Cirrus]" *every time* when messages are replied
to or forwarded.
The second line is supposed to prevent that, but in its current form
it only checks whether "[Cirrus]" appears right at the beginning of
the subject, preceded only by whitespace. If you don't want to add the
string any more as soon as it already appears *anywhere* in the
subject, change the line to
* ! ^Subject:.*\[Cirrus]
(Does the "]" have to be escaped here? I don't think so, but please
correct me if I'm wrong.)
/HW